Temperatures will reach the 90s and triple digits across most of the region Wednesday, with the peak of the heat expected Thursday and Friday.

The hottest areas will likely be the western San Fernando, Santa Clarita, Coachella and the Ventura County valleys, the National Weather Service said, while the coastal communities get highs in the 70s and 80s.

Isolated mountain and desert storms were also expected Wednesday.

A flash flood warning was issued for Palm Springs, and to the east a sand storm ripped through the Indio, followed by afternoon showers.

The weekend will bring slightly cooler weather, but temperatures will remain above normal, the NWS said.